Electromagnetic device



June 10, 1930. ED. MEAD ELECTROMAGNETIC DEVICE Filed May 6. 1929 W H L z,r

ATTORNEY Patented June 10, 1930 UNITED STATES PATENT OFFICE EDWARD D.MEAD, OI CALDWELL, NEW JERSEY, ASSIGNOR TO BELL TELEPHONE LAIB-ORATORIEB, INCORPORATED, NEW YORK, N. Y[, A CORPORATION 01' NEW YORKELECTROMAGNETIC DEVICE Application filed May 6, 1929. Serial No.860,717.

This invention relates in general to elec- 'tromagnetic devices and moreparticularly to a relay for responding to intermittent impulses ofcurrent. The object of the invention is the improvement in a relaystructure whereby the response to impulses over either a long circuithaving high resistance and considerable capacitance or over a shortcircuit is quick and reliable and the relay contacts are closed andopened positively without chattering.

In various electrical systems, particularly machine switching telephonesystems, it is necessary to transmit impulses for controlling thefunctions of switching apparatus over long circuits which may compriseseveral miles of wire. An impulse responsive relay to functioneffectively in such a circuit must be sensitive and positive in actionand must control its contacts in such a manner that theywill not chatterand thus produce false controlling impulses in local circuits controlledthereby.

In accordance with the present invention one embodiment of which hasbeen illustrated by way of example, the relay coma prises asubstantially U-shaped magnetic circuit having a winding on eachparallel leg thereof and an armature of slight inertia pivoted at itscentre to a non-magnetic yoke supported upon. the pole pieces. Thearmature is so pivoted as to swing between the pole pieces. The relay isprovided with a pair of contact springs each mounted in a stud at eitherend of the yoke, one being disposed on one side of the armature and theother on the other side of the armature and with their free contact endsopposite each other in substantial alignment with the armature pivot.

When the armature is rotated to move its poles toward the pole pieces,each end thereof engages the spring adjacent thereto, whereby the twosprings are moved toward each other into contact. Since both springs aremoved, the movement of each spring is made less than would have beennecessary if only one spring in the pair moved, thereby reducing thevelocity of the spring travel. Also, since the springs both move suringa firm chatterless engagement.

toward each other due to the manner in which they are mounted withrespect to each other and to the armature, there is a slight wipingaction of their contacts, thereby in- The invention will be more clearlyunderstood by reference to the accompanying drawing, in which Fig. l isa view in perspective of an electromagnetic device embodying theinvention; Fig. 2 is a top plan view showing the mounting of the contactsprings; and Fig. 3 is a view in perspective of an electromagneticdevice embodying a modified form of the invention.

Referring now to Fi s. l and 2 in which the preferred form 0 theinvention has been disclosed, the relay comprises a substantiallyU-shaped magnetic circuit having cores terminating at their forward endsin pole pieces 1 and 2 and joined at their rear ends by a heel-piece 3,to which the cores are united by the threaded portions 4 and nuts 5. Thepole pieces are flattened as at 6 to form air-gaps with the pivotedarmature 7 for completing the magnetic circuit. Mounted on each core isa spool 8 carrying a magnet coil 9, the two coils being connected inseries to provide an energizing circuit for the relay.

Supported upon the forward ends of the cores and resting upon the upperheads of the spools 8 is a yoke 10 of non-magnetic material. The yoke 10is provided with openings therein through which the pole pieces 1 and 2extend, the openings being of such area and connected by slots 11 withthe edges of the yoke so that the yoke when driven upon the pole piecesis held securely thereon. Extending upwardly and then inwardly from oneedge of the yoke 10 is a bracket 12. Pivoted between the end ofbracket'12 and the body of the yoke 10 an armature 7 is pivoted on thepin 27 and so disposed that its ends may oscillate toward and away fromthe pole pieces 1 and 2.

Extending upwardly from the edge of the yoke 10 opposite the bracket 12is a slotted lug 13 through which is threaded the stop pin 14: forlimiting the movement of the armature away from the pole pieces and for100 adjusting the air-gaps between the ends of the armature 7 and thefaces 6 of the pole pieces 1 and 2.

- Attached at each end of the yoke 10 by screws 16 is a block ofinsulating material 15. The screws 16 are more clearly shown On each endof the upper side of the ary mature 7 an insulating roller 21 isrotatably attached by a pin 22. Normally the springs 19 and 20 pressupon the rollers 21 to cause the armature 7 to swing its ends away fromthe pole pieces until stopped by the stop pin 14. "When the circuitthrough the coils 9 is closed the ends of the armature 7 are attractedtoward the faces 6 of the pole pieces 1 and 2, whereby the rollers 21carried by the armature move the free ends of the contact springsagainst their normal tension. Since the contact ends of the springs 19and 20 are oflst with respect to their points of attachment to the lugs18, they are through the attraction of the armature 7 moved intoengagement With each other, as will be clearly apparent by referring toFig. 2. Notonly are the contact ends brought into a firm engagement witheach other, but due to the conformation of the springs a slight wipingaction between the contacts results whereby the contact surfaces arekept free from dust particles. Since the two springs move toward eachother into engagement the travel of each spring is reduced to half ofthe travel that would be necessary ir one contact spring only weremovable, as is the usual relay contact spring arrangement.

The armature 7 may be made very light so that it has very small inertiawhereby the relay is very quick to make and break the contact betweenits contact springs and is exceptionally free from any tendency to causea chattering of the contacts.

The modified form of the invention shown in Fig. 3 is similar to theform of the invention just described with the exception of thearrangement of the contact springs '19 and 20 and armature 7. Thesprings 19' and 20 are each welded, soldered or otherwise secured in theslotted ends of studs 23, which are screwed into the insulating blocks15 and locked therein by lock-nuts 24. Each spring is provided with apair of lugs 25, between which is pivoted a roller 21 of insulatingmaterial. For engagement with the roller 21 of each spring the pivotedarmature 7 is provided at each end with an upwardly extending member 26.This relay functions in the same manner as-the relay previouslydescribed.

VVhat is claimed is:

1. In an electromagnetic device a magnetic circuit comprising a coreterminating in a pole-piece and a pivoted armature oscillatable towardand away from said pole-piece, a pair of contact springs one disposed oneither side of the pivot of said armature, said springs extending towardeach other with their free contact ends disposed opposite each other,and means operable through the oscillation of said armature to move thecontact ends of both said springs toward each other into engagement.

2. In an electromagnetic device a magnetic circuit comprising a coreterminating in a pole-piece and a pivoted armature oscillatable towardand away from said polepiece, a pair of contact springs one disposed oneither side of the pivot of said armature, said springs extending towardeach other with their free contact ends disposed opposite each other,and means operable throu h the oscillation of said armature to move t econtact ends of both said springs toward each other into a wipingengagement.

3. In an electromagnetic device, a magnetic circuit comprising asubstantially U- shaped core and a pivoted armature oscillatable betweenthe pole pieces of said core, a pair of contact springs, one disposed oneither side of said armature, said springs extending toward each otherwith their free contact ends disposed opposite each other, and" meansoperable through the oscillation of said armature to move the contactends of both said springs toward each other into engagement.

4. In an electromagnetic device, a magnetic circuit comprising asubstantially U- shaped core and a pivoted armature oscillatable betweenthe pole pieces of said core, a pair of contact springs, one disposed oneither side of said armature, said springs extending toward each otherwith their free contact ends disposed opposite each other, and meansoperable through the oscillation of said armature to move the contactends of both said springs toward each other into a wiping engagement.

5. In an electromagnetic device, a ma netic circuit comprising asubstantially U-sliaped core and a light pivoted armature oscillatablebetween the pole pieces of said core, a pair of contact springs onedisposed on either side of said armature, said springs extending towardeach other with their free contact ends disposed opposite each other,and means operable through the oscillation of said armature to move thecontact ends of both said springs toward each other into engagement.

sprin each other wit their ee 6. In an electromagnetic device amagneticcircuit comprising a substantially U- aped core and a pivotedarmatureosci'llatable between the pole pieces of said core, a pair ofcontact springs one dis osed on either side of said armature, sai srings extending toward each other with t eir free contact ends disposedopposite each other, and rollers interposed between the ends of saidarmature and said s rin for moving the contact ends of bot said springstoward each other into engagement through the oscillation ofsaidarmature. i

7 In an electromagnetic device a magnetic circuit comprising asubstantially U- shaped core and a pivoted armature oscillatabie betweenthe pole pieces of said core, a

pair of contact springs one disposed on either side of said armature,said springs extending toward each other with their free contact endsdisposed opposite each other, and rollers mounted upon the ends of saidarmature for engaging said springs for moving the contact ends of bothsald springs toward each other into engagement through the oscillationof said armature.

'8. In an electromagnetic device a ma netic circuit comprising asubstantially shaped core and a pivoted armature oscillatable betweenthe pole pieces of said core, a non-magnetic yoke supported upon thecore through which said'pole pieces extend, said armature being-pivotedat its center to said yoke, insulating. blocks mounted upon the ends ofsaid yoke, a'contact spring supported by each block, said springsextending toward each other with their free contact ends dis osedopposite each other, and means opera le through the oscillation of saidarmature to move the contact ends a bracket formed integrally with saidyoke between which and the body of said yoke of both said springs towardeach other into core through which the polepieces extend, a

bracket formed integrally with said yoke between which and the" body ofsaid yoke J said armature is pivoted to oscillate freely, lnsulatingblocks mounted upon the ends of said yoke, a contact spring supported byeach block, sai

posedopposite each other, and means operable through the oscillationofsaid armature to move the contact ends of both said springs towardeach other into engagemcnt.

extending toward contact. ends dis-,-

1 In an electromagnetic device a m netic circuit comprising asubstantially sha d core anda pivoted armature oscil lata le between thepole-pieces of said .core,

a non-magnetic yoke supported upon the core through which thepole-pieces extend,

